Refrigeration Formulas

Front 1

Total heat transfer

Back 1

(4.5 x cfm x change in heat) = Qt

Hint 1

Constant of 4.5

Front 2

Sensible Heat Transfer

Back 2

(1.08 x cfm x change in temperature)

Hint 2

Constant of 1.08

Front 3

Average velocity

Back 3

(Square root of velocity x 4005)

Hint 3

Square root of the water column measurement, multiplied by 4005.

Front 4

Area of a circle

Back 4

Pi x radius^2

Hint 4

Pi r squared

Front 5

Volume flow rate

Back 5

Average velocity • duct area = cfm

Hint 5

Av•da=cfm

Front 6

Compression Ratio

Back 6

SDP/SSP

Hint 6

Saturated discharge pressure divided by saturated suction pressure

Front 7

Combined Gas Law

Back 7

P1•V1•T2=P2•V2•T1

Front 8

Coefficient of Performance

Back 8

NRE/HOC

Hint 8

Higher the CoP the better

Front 9

Coefficient of Performance

Back 9

NRE/HOC

Hint 9

Higher the CoP the better

Front 10

Mass flow rate

Back 10

M=200/NRE (per ton)

Hint 10

Unit is lb/min

Front 11

Temperature drop

Back 11

Air entering - air leaving

Hint 11

Evaporator

Front 12

Temperature drop

Back 12

Air entering - air leaving

Hint 12

Evaporator

Front 13

Temperature rise

Back 13

Air leaving - air entering

Hint 13

Condenser

Front 14

Temperature drop

Back 14

Air entering - air leaving

Hint 14

Evaporator

Front 15

Temperature rise

Back 15

Air leaving - air entering

Hint 15

Condenser

Front 16

Temperature difference

Back 16

Air entering - saturation temperature

Hint 16

Evaporator temp difference

Front 17

Temperature drop

Back 17

Air entering - air leaving

Hint 17

Evaporator

Front 18

Temperature rise

Back 18

Air leaving - air entering

Hint 18

Condenser

Front 19

Temperature difference

Back 19

Air entering - saturation temperature

Hint 19

Evaporator temp difference

Front 20

Condensor Temperature difference

Back 20

Refrigerant - air entering

Hint 20

Two different substances temp difference

Front 21

Temperature drop

Back 21

Air entering - air leaving

Hint 21

Evaporator

Front 22

Temperature rise

Back 22

Air leaving - air entering

Hint 22

Condenser

Front 23

Temperature difference

Back 23

Air entering - saturation temperature

Hint 23

Evaporator temp difference

Front 24

Condensor Temperature difference

Back 24

Refrigerant - air entering

Hint 24

Two different substances temp difference

Front 25

Kpaa to psia

Back 25

KPAA/6.89

Hint 25

Kilopascal absolute over 6.89

Front 26

Psia to Kpaa

Back 26

Psia • 6.89

Hint 26

Psia absolute multiplied by 6.89

Front 27

Temperature drop

Back 27

Air entering - air leaving

Hint 27

Evaporator

Front 28

Temperature rise

Back 28

Air leaving - air entering

Hint 28

Condenser

Front 29

Temperature difference

Back 29

Air entering - saturation temperature

Hint 29

Evaporator temp difference

Front 30

Condensor Temperature difference

Back 30

Refrigerant - air entering

Hint 30

Two different substances temp difference

Front 31

Kpaa to psia

Back 31

KPAA/6.89

Hint 31

Kilopascal absolute over 6.89

Front 32

Psia to Kpaa

Back 32

Psia • 6.89

Hint 32

Psia absolute multiplied by 6.89

Front 33

Psia to psig

Back 33

Psia - 14.7

Hint 33

Psia subtract absolute

Front 34

Temperature drop

Back 34

Air entering - air leaving

Hint 34

Evaporator

Front 35

Temperature rise

Back 35

Air leaving - air entering

Hint 35

Condenser

Front 36

Temperature difference

Back 36

Air entering - saturation temperature

Hint 36

Evaporator temp difference

Front 37

Condensor Temperature difference

Back 37

Refrigerant - air entering

Hint 37

Two different substances temp difference

Front 38

Kpaa to psia

Back 38

KPAA/6.89

Hint 38

Kilopascal absolute over 6.89

Front 39

Psia to Kpaa

Back 39

Psia • 6.89

Hint 39

Psia absolute multiplied by 6.89

Front 40

Psia to psig

Back 40

Psia - 14.7

Hint 40

Psia subtract absolute

Front 41

Kpaa to kpag

Back 41

Kpaa - 101.325

Hint 41

Kpaa minus absolute kilopascal

Front 42

Vacuum

Back 42

(14.7-psia)2.04

Hint 42

Inches of mercury vacuum

Front 43

Kelvin to Rankine

Back 43

K • 1.8

Hint 43

Kelvin multiplied by 1.8

Front 44

Rankine to Kelvin

Back 44

R/1.8

Hint 44

Rankine over 1.8

Front 45

Kelvin to Rankine

Back 45

K • 1.8

Hint 45

Kelvin multiplied by 1.8

Front 46

Rankine to Kelvin

Back 46

R/1.8

Hint 46

Rankine over 1.8

Front 47

Celsius to Kelvin

Back 47

C° + 273

Hint 47

Celsius added to 273

Front 48

Kelvin to Rankine

Back 48

K • 1.8

Hint 48

Kelvin multiplied by 1.8

Front 49

Rankine to Kelvin

Back 49

R/1.8

Hint 49

Rankine over 1.8

Front 50

Celsius to Kelvin

Back 50

C° + 273

Hint 50

Celsius added to 273

Front 51

Fahrenheit to Rankine

Back 51

F + 460

Hint 51

460

Front 52

Kelvin to Rankine

Back 52

K • 1.8

Hint 52

Kelvin multiplied by 1.8

Front 53

Rankine to Kelvin

Back 53

R/1.8

Hint 53

Rankine over 1.8

Front 54

Celsius to Kelvin

Back 54

C° + 273

Hint 54

Celsius added to 273

Front 55

Fahrenheit to Rankine

Back 55

F + 460

Hint 55

460

Front 56

Celsius to Fahrenheit

Back 56

(C°x1.8)+32

Hint 56

Celsius multiplied by 1.8 add 32

Front 57

Fahrenheit to Celsius

Back 57

F-32

-----

1.8

Hint 57

Subtract 32 and divide by 1.8

Front 58

Btu for steam

Back 58

970 btu

Hint 58

High

Front 59

Freeze btu

Back 59

144 btu

Hint 59

Low

Front 60

Gallons per hour

Back 60

Back (Definition)

Front 61

Thermodynamics

Back 61

pV=mRT

Hint 61

M= mass

P= pressure

R= the gas constant

T= temperature

V= volume